Radioreceiver



July 30, 1929. M. J. JELEN RADIORECEIVER Filed July 20. 1928 l NVENTORATTORNEY Patent July so. 19.

MATT J. JELEN, OF CHICAGO, ILLINOIS, ASSIGNOR TO STEWART-WARNER CORPORA-TION, OF CHICAGO, ILLINOIS, A CORPORATION OF VIRGINIA.

RADIORECEIVER.

Application filed July 20,

Among the objects of my invention are the provision of a means foreffectively controlling volume, a means for cont-rolling regenerationand a means for coordinating these two controls so that they may beadjusted simultaneously by a single operation.

In the modern highly perfected radio receiver, it is essential thatthere should be an effective volume control which will operate withoutdisturbing the working voltages, the

- tuning of the various circuits, etc. It is also essential that controlof regeneration should be had by some means both effective and simple tooperate. A third requirement is that there should be few manuallyoperated controls and that the set should be made as automatic andfool-proof as possible.

By my invention I control both volume and regeneration by means of asingle manual adjustment. The actual tuning of the set may also becontrolled by a single manual adjustment through mechanical coupling ofthe tuning condensers of the various stages in the well known manner.

Referring to the drawings:

Fig. 1 is a wiring diagram of a radio receiving circuit illustrating a,volume control in the form of a resistance in the antenna circuit.

Fig. 2 is a similar diagram with the addition of a regeneration controlin one of the grid circuits, and

Figs. 3 and 4 are similar diagrams ,illust-rating two ways in whichthese controls may be combined into an operatively single unit inaccordance with my invention.

A means by which a convenient and smooth acting control of volume may behad without otherwise affecting the receiver, is illustrated in Figure 1of the accompanying drawings, in which is shown the first stage of aradio frequency amplifier and part of the second stage of generallyconventional form. The antenna 1 is coupled to the circuit of the firstradio frequency tube 2 by the usual coupling transformer 3. The. secondstage is coupled to the first in the usual manner by means oftransformer 4. Control of volume is effected by a variable resistor 5connected in parallel with the primary winding 6 of transformer 3. Bychanging the effective resistance of resistor 5, a eater or less amountof the energy picke up by the antenna will be byassed to the groundaround the primary Wm mg 6.

1928. Serial No. 294,107.

The higher the effectiveresistance of resistor 5 is made the less energywill be by-passed and vice versa. By this means the amount of energypermitted to pass through the primary 6 of transformer 3 and,consequently, the amount of energy which will be fed to the grid ofaudion 2, can be varied over a wlde range and a simple and efficientcontrol of volume obtained.

Regeneration may be controlled by increasmg or decreasing the resistancein the grid circuit of one of the stages of the amplifier. Increasingthe resistance will reduce the amount of regeneration whereas decreasingthe resistance will permit of .a greater degree of regeneration. Asuccessful and simple regeneration and partial volume control based uponthis principle is illustrated by Figure 2 which shows a circuitgenerally similar to that of Figure 1 with the exception that in thegrid return lead of audion 8 has been inserted a variable resistor 7 inseries with the secondary winding of transformer 4. The amount ofregeneration may be reduced by increasing the effective value ofresistor 7 and vice versa.

From the above it is apparent that the amount of energy delivered to thereceiver from the antenna and, consequently, the volume of the soundsdelivered to the loud speaker may be controlled by varying the effectivevalue of resistance 5. Also that the amount of regeneration may becontrolled by varying the effective value of resistor 7. It will also beevident that the effect 'of the two resistances are opposite, that is tosay, an increase in the effective value of resistance 5 results in anincrease in the amount' of energy delivered to the first tube, whereasan increase in the efiective value of resistance 7 results in a decreasein regeneration. This being so, both the volume control and theregeneration control may be combined into a single unit, namely, asingle resistance with a sin le variable element so that they may both esimultaneously adjusted by a single operation.

One application of my invention is illustrated by Figures 3 and 4.in theaccompanying drawings. In Figure 3 it will be seen that the volumecontrol shown in Figures 1 and 2, namel a variable resistance 5 inparallel with t e primary winding 6 of transformer 3 has been used. Theregeneration control shown in Figure 2 which comprises a variableresistance 7 associated with the secondary of transformer 4 has alsobeen retamed. However, in thls instance, the two reslstances 5 and 7have been combined into a single re-- sistance with a single variableelement 9. Since one end of the variable resistance is connected to thegrid return of tube 8 and the other end to the antenna side of windin 6of transformer 3, any adjustment of varia le arm 9 will cause a changein resistance, both in the volume control circuit and in theregeneration control circuit. When the resistance in the volume controlcircuit is increased, the resistance in the regeneration control will bedecreased and vice versa. It will be readily apparent to. those skilledin the art that, for the effective operation of a radio receiver,regeneration should be increased for weak signals and decreased forstrong signals. By the method which I have invented and described, thecontrol of volume and regeneration is accomplished in accordance withthis principle by a single operation.

Figure 4 illustrates a modification of my invention as shown in Figure 3which permits of an independent preliminary adjustment of the efiectivevalues of resistors 5 and 7 to meet the varying conditions encounteredby radio receiver's. Here the resistors 5 and 7 are not combined into asingle resistance as in Figure 3, but are kept separate as in Figures 1and 2. Also each has itso'wn adjustable arm 10 and 11 by means of whicha greater or less proportion of each resistance may be included in thecircuit. These two arms 10 and 11, however, are electrically connectedto each other and to the conductor 12 through a common lead 13. Inoperation, arms 10 and 11 are locked together by any convenient means sothat they may be adjustedsimultaneously by means of a single control.Arms 10 and 11 may, however, be individually adjusted so that the ratioof resistance 5 to resistance 7 may be regulated to suit the desiredconditions of volume and regeneration. Individual adjustment may be madepossible by securing arms 10and 11 to their common shaft by means of setscrews or in any other convenient manner.

I do not intend to limit my invention to the exact arrangement of partsand circuits described. It will be evident to those skilled in the artthat my invention may be employed in many other circuits withoutdeparting from its essential features.

I claim:

1. Aradio receiving circuit including a multi-electrode audion, a tunedgrid circuit therefor, means for coupling said grid circuit to anantenna circuit, variable means associated with said antenna circuit forby-passing to ground more or less of the energy received, variable-meansin said grid circuit for controlling regeneration, and means wherebyadjustment of said by-pasing means will cause a concurrent automaticadjustment of said regeneration control.

2. A radio receiver, comprising two or more multi-electrode audions incascade, an antenna circuit coupled to the grid circuit of the firstaudion, means associated with said antenna circuit for by-passing toground any part of the energy therein, means associated with a gridcircuit for controlling regeneration, said by-passing and regenerationcontrolling means being concurrently operable by a. single control.

3. A radio receiving circuit including two or more multi-electrodeaudions in cascade, an antenna circuit coupled to the grid circuit ofthe first audion, a variable resistance in parallel with said antennacircuit for by-passing to ground any part of the energy therein, avariable resistance in a gridcircuit for controlling regeneration, andmeans whereby said variable resistances may be concurrently varied by asingle control.

4:. In a radio receiving circuit employing multi-electrode audions, acombined volume and regeneration control comprising a resistance inparallel with the antenna circuit, a resistance associated with a gridcircuit, a movable element for each resistance for varying the effectiveresistance of 'one in inverse relation to that of the other, saidmovable ele ments being concurrently operated as a unit by a singlecontrol.

5. In a radio receiving circuit employing mu'lti-electrode audions, acombined volume and regeneration control comprising a resistance inparallel with the antenna circuit, a resistance associated with a gridcircuit, a movable element for. each resistance for varying theeffective resistance of one in inverse relation to that of the other,said movable elements being concurrently operated as a unit by a singlecontrol and also being capable of independent adjustment whereby theratio of the effective resistance of one to that of the other may bevaried.

6. In a radio receiving circuit employing multi-electrode audions in twoor more transformer coupled stages, a combined volume and regenerationcontrol comprising a variable resistance in parallel with the primaryWinding of the input transformer, a variable resistance in a gridcircuit, means for adjusting the relative efi'ective values of saidresistances and unitary means for varying both of said resistancesconcurrently and in-- versely.

MATT J. JELEN.

